Improvement in rock-drills



, tion, in which- 'UNITED STATES PATENT OFFICE.

O. B. LATHAM, OF SENECA FALLS, NEW YORK.

IMPROVEM ENT IN ROCK-DRILLS.-

Specification forming part of Letters Patent No. 49,281, dated August8,1865.

l'o all whom it may concern:

Beit known that I, O. B. LATHAM, of Seneca Falls, in the county-ofSeneca and State of New York, have invented new and useful Im- Figure lis a perspective view. Fig. 2 is a vertical section, and Fig. 3 aperspective view of the reamers.

This drill, in its general form and structure,

resembles those in common use, consisting ot' the body A, bit B, andscrew-shank O.

At right angles to the edge of the bit I make a mortise through the bodyA, about four or ve inches, or more, according to the size of the drill,above the edge of the hit B.` The lower end of this mortise isdovetailing, being deepest in the center, as shown at D in Fig. 2. E inthe several views represents the reamers. These consist of temperedpieces of steel or other material, each section ot' which is made sothat either end will accurately t one-halt' of the mortise, asshown inFig. 2-that is, when both sections of the reainer are placed in themortise the inner and longer faces will Vmeet at the center of the bodyof the drill. These reamers E extend outward from the body of the drillso that their united width from e to e shall be equal to or a littlemore than the Width of the edge of the bit B. The outer corners of thereamers are formed at right angles, as shown at a, both above and below,so that they can be reversed in their position, and thuspresenting asharp, angle when the lower one becomes worn, the lower end of thereamer being always exposed to the most friction. In this way-the samereamers become self-sharpening, and can be frequently turned so as topresent a good cutting angle, the wear upon the outer faces beingcompensated for by the introduction of thin pieces of metal placedbetween the sections, as shown at c in Fig. 2.-

'Ihe reamers are held in place by a gib, F, V the lower face of which isfitted to the end of" the reamers E, as shown in Figs. 2 and 3. Bothends of the gib haveT-heads, as shown in Fig. 3, which embrace bothsides ot' thebcdy of the drill, thus making it secure. Thegib is heldin. place by a -Key, Gr, in the usual manner; It will be observed byreference to the shape of the mortise at the lower end and the shape ofthe lower face of the gib that the reamers will always adjust themselvesto their central position. The reainers thus constructed act upon the.sides ot' the bore both in rising and fallin g, but mostly, o f course,in their descent. The reamers thus constructed also act as a guide tothe d1ill,'and prevent the forming ot' a triangular hole, even shouldthey not perform the office of reaming out the bore.

What I claim as my improvement, and' desire to secure. by LettersPatent, is

Constructin g the reamer with cutting-angles both above and below,making them reversible and adjustable in the body of the drill,substantially as specified. h

'OBADIAH B. LATHAM.

Witnesses:

EDM. F. BROWN, S. J. BOWEN.

